On Tue, Jul 26, 2022 at 05:15:13PM -0700, Soumya Negi wrote:

Fix Syzbot bug: kernel BUG in ntfs_lookup_inode_by_name https://syzkaller.appspot.com/bug?id=32cf53b48c1846ffc25a185a2e92e170d1a95d7...

Check whether $Extend is a directory or not( for NTFS3.0+) while loading system files. If it isn't(as in the case of this bug where the mft record for $Extend contains a regular file), load_system_files() returns false.

Reported-by: syzbot+30b7f850c6d98ea461d2@syzkaller.appspotmail.com CC: stable@vger.kernel.org # 4.9+ Signed-off-by: Soumya Negi soumya.negi97@gmail.com

---

Changes since v1:

• Added CC tag for stable
• Formatted changelog to fit within 72 cols

---

fs/ntfs/super.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c index 5ae8de09b271..18e2902531f9 100644 --- a/fs/ntfs/super.c +++ b/fs/ntfs/super.c @@ -2092,10 +2092,15 @@ static bool load_system_files(ntfs_volume *vol) // TODO: Initialize security. /* Get the extended system files' directory inode. */ vol->extend_ino = ntfs_iget(sb, FILE_Extend);

• if (IS_ERR(vol->extend_ino) || is_bad_inode(vol->extend_ino)) {

• if (IS_ERR(vol->extend_ino) || is_bad_inode(vol->extend_ino) ||

•    !S_ISDIR(vol->extend_ino->i_mode)) {
  

• static const char *es1 = "$Extend is not a directory";
  

• static const char *es2 = "Failed to load $Extend";
  

• const char *es = !S_ISDIR(vol->extend_ino->i_mode) ? es1 : es2;
  

• if (!IS_ERR(vol->extend_ino)) iput(vol->extend_ino);

• ntfs_error(sb, "Failed to load $Extend.");
  

• ntfs_error(sb, "%s.", es);
  

  goto iput_sec_err_out; }

#ifdef NTFS_RW

2.17.1

Hi Anton, Have you had a chance to look at this patch?

Thanks, Soumya